Fit perfect, works great, definitely replace when you replace the lower hose.

I recently had my coolant diagnosed as a condemned radiator, along with nearly all the other components of the cooling system. One of those items was the fan switch. I did a google search and discovered it here for a great price. I installed it will all the other components and the only issue I've had is a check engine light from the thermostat I bought at ECS Tuning. I recommend dealing with FCP Euro because of their unbeatable warranty, ease of use and great prices.

Must have if you are changing your lower radiator hose. I tried to remove the original just to see if I had made a good purchase, broke right in half. I would have been stuck without this piece. Snaps into place easily.

Fits into lower radiator hose perfectly with the BMW Green O-ring installed. It does come with a black O-ring that I am keeping as backup.

Water pump failed on my '07 328Xi and was I able to shutdown within seconds to avoid serious engine damage. Replaced failed water pump with water pump kit and replaced this switch (along with other affected parts) to assure a successful job. When these switches are overheated they will tend to send erroneous signals to the DME which will cause the electric fan to run at various speeds or even at full speed all the time.